Fps issues in game

Recently I noticed that i'm getting below 144 fps consistently in game, This is a massive problem for me because I have a high end computer that should be able to get more Fps. Especially in teamfights it goes down to the 60's, and when you consider that I have a 165Hz Monitor, I can really feel the drop and this affects me in game. I have become annoyed of this and have tried the following: Reinstalling league of legends, updating drivers (Clean Installation), using the Nvidia control panel in the League of Legends profile to make sure the power management is always at, "Prefer Maximum," I have the Windows Game Bar disabled and nothing playing in the background. I have noticed in the task manager that my GPU usuage in game Peaks around 15% and my CPU usuage doesn't go about 25%, so I know i have more resources available to increase my fps, but it's not being used. This has really been annoying me recently and is effecting my performance in game. So I would love a response very quickly, i'm open to trying almost anything at this point with this issue. I also notice if I change the resolution from anywhere to 720p all the way up to 4k the Fps does not change at all and stays the same.

My Specs Msi GTX 1070 I5 6600k Overclocked to 4.0 8Gb of dual channel ddr4 3000mz ram the hardrive it is installed under is the Samsung 850evo 1440p, 165hz monitor with G-Sync Windows 10 64 bit

Let me know if you need anymore information and I will be glad to answer.

EDIT: after tons of optimizations to my computer I gained 10 fps, but the drops still go down.